Of Laptops, Embedded Controllers, and mini PCI-express cards

I recently purchased an Acer Aspire One 725-802 (some partial decoding of Acer’s terrible numbering scheme: C-60 CPU, 2GB mem, 2.4GHz wifi, no Mobile Wireless). Having previously purchased 2 mini pci-e wifi cards which support both 2.4GHz & 5GHz, I decided to swap out the netbook’s included mini pci-e wifi card for one of mine.

Kindly enough, there is only a single screw holding the rear covering of the laptop, which I removed to see the 1 occupied half height mini pci-e slot as well a unoccupied full height slot (with no connector to slide a card into).

So I wouldn’t get to put 2 wifi chips in my computer today, but surely I’d just buy a connector later on, solder it in, and add an SSD or something of that sort.

So, back to the included wifi chip: I swapped it with one of the ones I’d purchased online, reattached the antennas, closed it up, and turned the computer on.

Interestingly, it appeared to take longer to come up to the ‘Acer’ bios splash screen.

And then I realized my keyboard wasn’t working.

After trying the other wifi chip, trying the original again, and several full power downs by pulling the battery, I’m left with the following conclusion:

When either of my 2 replacement wifi chips were in the computer at boot time,
the keyboard eventually stopped working. Sometimes I could navigate the boot
menu quickly enough that Linux would begin to boot. But I would be unable to
interact with the command line once booting had finished. Interestingly, the
only key that seemed to work was a FN+F5, which toggles the backlight. Clearly
something was getting my key presses. At least some of them. But why weren’t
they getting out?

My current suspicion is that the embedded controller is doing something particularly nasty to block the use of non-Acer mini pci-e cards.